rpm- mpg ??

[ken kindle]

kbkindle here i have a 2004 200 hpdi small block yamahie running on a 2002 ranger 195dvs
last year it ran 5400 rpm's at 63 mph at wot this year same boat and same equipment it runs at 5000rpm at 57mph running a 25 m prop have done nothing to boat or motor. i really dont care about speed but a'm i running into a problem
motor runs smooth and sweet thank you ken kindle

[jonp]

Hi Ken,

Hard to say if you are running into a problem. I had a Hydrostream with a Merc 175HP. I did have a few issues with fuel delivery when early on. It kind of did the same thing, just would not reach normal RPM's. Normally trimmed out it would go to 5800. That was solved, by repalcing the lines and keeping the tank and carbs clean. I had a water issue as well, water getting in thru the vent... That was a pain to figure out.

Also I periodically repalced the fuel pump during the time I had it. As the engine aged I could only get about 5600/5700. It was 20 years old, and still running over 60MPH until I sold it this season.

Note that if it is running lean you could shorten the life of the engine. The plugs will tell you if you are lean. Kind of dry and light gray/white looking.

Good luck
Jon